Is that really necessary? Hitting with the fleshy part of your hand on an inflateable bag doesn’t seem to be taking a toll on my hands.
Wraps are primarily for your wrists… 
its all good you can do it either way. I do find that wearing wraps give you a more snapier pop on the bag but not enough to recommend the proper way is to wear wraps. If youre in for a challenge though wear your gloves while hitting the speedbag